Generally, a plastic container called a PET bottle is heavily used for commercialization, transportation, storage, and so forth, of a drinking water such as a mineral water, and other liquids. It is pointed out, however, that this kind of plastic container is light in weight and high in safety, but is bulky and hard to handle because it is high in rigidity and keeps in a fixed shape regardless of an amount of the contents. As opposed to such a container, a flexible container in bag shape, formed of a plastic film, has been in widespread use. The flexible container is high in holding efficiency in a box or like because it undergoes variation in external shape due to fluidity of its contents, and the flexible container by itself after use is easy to handle because it is small in volume and can be optionally folded and overlaid one on top of another, thereby rendering it less bulky than the PET bottle. Further, the flexible material can be easily scrapped depending on the quality of the contents, and hence it is excellent in ambience.
For example, as shown in FIG. 13, a flexible container 200 in which mineral water is contained has a holding part 202 formed of a flexible material, as the holding part 202 is sealed at upper and lower seal parts 204, 206 by thermo compression bonding. The flexible container 200 employs a synthetic resin sheet such as polyethylene and so forth which is excellent in tearing property. Slits 208 and 210 are formed in the seal part 204 at the two corner sides of the holding part 202, and an arrow 212 indicating a tearing direction of the holding part 202, namely, a direction for opening the holding part 202 from the seal part 204 to the holding part 202, is printed on the holding part 202.
With the flexible container 200 having such a configuration, if a tearing force is applied to a direction of the arrow 212 for opening the cut 208 while picking up both sides of the slit holding part 208 as shown in FIG. 14, the seal part 204 and a part of the holding part 202 are torn so that the holding part 202 in which water is contained is broken to open the holding part 202. Further, as shown in FIG. 15, likewise, the holding part 202 can be opened by tearing the cut 208 in a direction of an arrow 212 while picking up both sides of the cut 208 after a flexible container 200 is put in a stand 214 serving as a reinforcing container. In the case where the stand 214 is used, the holding part 202 can be opened by applying a force to the seal part 204 so as to open the cut 208 with one hand in FIG. 15.
Meanwhile, if the flexible container 200 is formed of a flexible material which is excellent in tearing property, it can be easily opened but the shape of the opening formed by opening the holding part 202 is not uniformized depending on a tearing direction. For example, as evident from each shape of breakage piece 216 formed by being opened from the cut 208 and torn, as shown in FIG. 16(A), 16(B) and 16(C), each opening 218 is variously shaped so that the shape of the opening 218 becomes asymmetrical about the seal part 204 or distorted. If water serving as an contents is to be poured into a cup or the like from the opening 218, a direction of water is changed depending on the shape of the opening 218, resulting in trouble in handling such fail in pouring water into the cup or the like.
Further, in the case shown in FIG. 17, since a holding part 202 is soft, an opening 218 is easily sealed by a clip 220 to prevent water from flowing out, and sealing of the holding part 202 can be easily released by removing the clip 220. In this case, if a flexible container 200 sealed by the clip 220 is kept in a refrigerator, the opening 218 to which sealing pressure is applied is hardened by refrigeration and kept in an close contact state, even if the clip 220 is removed from the opening 218 in the case where a flexible container 200 is formed of a flexible material such as a synthetic resin sheet. Accordingly, there is disadvantage that shaping of the opening 218 takes time when using the flexible container 200 or if a user intends to flow out water through the opening 218 by inclining the flexible container 200 in the close contact state, water is prevented from flowing out, and a flowing direction of water is hardly operable.
Still further, in the case where the opening 218 is sealed by such a clip 220, if an opening area or an opening width of the opening 218 is varied with an arbitrary tearing force, there is a likelihood that the opening 218 can not be sealed by the intended clip 220.